Thread slack mechanism for sewing machines



THREAD SLACK MECHANISM FOR SEWING Filed Nov. 23, 1962 MACHINES 2 Sheets-Sheet l FIGJ.

%NVENTOR5 \J ATTCRNEY y 13, 1965 LR. KREMER ETAL 3,194,195

THREAD SLACK MECHANISM FOR SEWING MACHINES Filed Nov. 23, 1962 2 Sheets-Sheet 2 FIGA INVENTORS Irl/Up K. remerw ATTORNEY tive to provide for looseness or slack two threads together. The needle and vertically and draws the bottom or bobbin thread tightly against the lowersurface of the fabric, thus form- United States Patent 3,194,195 THREAD SLACK MECHANISM FOR SEWING MACHINES Irvin R. Kremer, Schuylkill Haven, and William E.

Dellrer, Pottsville, Pa., assignors to Phillips-Van Heusen Corporation, New York, N.Y., a corporation of New York Filed Nov. 23, 1962, Ser. No. 239,703 4 Claims. (Cl. 112-154) This invention relates to thread slack mechanism for sewing machines and more particularly to means operain the loops of the stitching produced by the machine.

In the present art of machine sewing, the needle and thread pierce the fabric and pass through it so that the eye ofthe needle extends beyond the lower face of the cloth. At that time, the hook from the bobbin catches the thread, pulls it down and passes the bobbin thread through the loop in the needle thread, thus engaging the then moves upwardly ing the stitch.

The sewing thread, during the above-described stitching operation, is under some tension in order to produce a smooth, flat-appearing seam. The tension used in sewing may vary, but it tends to stretch the thread and thus adds to the potential shrinkage of the thread later. If

the tension is removed or materially reduced, the machine may not sew well at high speed, nor will the seam have a good appearance on its face.

When a seam .is made in the conventional manner as above described, and with the stitching relatively tight, shrinkage of the thread in the seam occurs when the garment is washed, and as a result the fabric of the garment becomes puckered along the seam. It is important in many garments, such as various types of outer garments, that such puckering be prevented since it materially detracts from the appearance of the garment. This is particularly true of garments which are intended to be used with little or no ironing, since puckering causes an unsightly appearance in the sewn areas and may require ironing of the garment to eliminate it. -It is therefore one of the objects of the invention to provide a means for sewing by which a certain regulated amount of looseness may be provided in both the upper and lower loops of the thread forming a seam, thereby making the thread of the same will be disposed flatly and evenly against shrinkage so that after washing of the garment the loops of the same will be disposed flatly and evently against both faces of the fabric; the appearance of the seam will be normal and there will be no puckering along the line of the seam.

In the co-pending application of Ainslie and Kremer, Serial No. 172,494, filed February 12, 1962, now Patent No. 3,130,696, issued April 28, 1964, there is disclosed a means for providing for slack or looseness in the upper loops of the thread which form a seam, and the present invention comprehends the provision of means by which such slack or looseness is lower loops.

More particularly, the invention contemplates the pro provided in both the upper and vision of a presser foot provided with elements disposed at right angles to the needle or needles of the machine ice and over which elements the upper loops in the seam are formed to thereby produce the required looseness in said loops, and of means similar tothe means disclosed in the above mentioned application for patent, for providing for looseness in the lower loops of the seam. C

With these and other objects to be hereinafter set forth in view, we have devised the arrangement of parts to be hereinafter set forth and more particularly pointed out in the claims appended hereto.

In the accompanying drawings, wherein an illustrative embodiment of the invention is disclosed,

FIG. 1 is .a front elevational view of the head of a sewing machine, with some of its parts omitted, and to which the present improvements have been added;

FIG. 2 is a side elevation of the structure shown in FIG. 1;:

FIG. 3 is a perspective view of the presser foot and the loop-engaging pins which are carried by the presser foot;

FIG, 4 is a top FIGS. 1 and 2;

FIG. 5 is an enlarged sectional view, taken substantially on the line 5-5 of FIG. 2, looking in the: direction of the arrows, and

FIG. 6 is a top plan view of the presser foot.

In a seam as convention-ally applied by the usual sewring machine, the loops of the thread are drawn taut and snugly against the opposite faces of the fabric. As a result, shrinkage of the thread causes undesirable puckering of the fabric in the vicinity of the seam. By means of the structure of the present invention, rods or pins are inserted within the upper and/or lower loops in the thread which forms the seam, with such rods or pins being momentarily maintained in each loop, and as a result, a regulatable amount of slack or looseness is provided in the thread which forms the loops.

The invention also contemplates the provision of means for releasing tension on the thread at the proper time so that the additional thread required for the formation of the desired slack or looseness in the loops, is pulled from plan view of the structure shown in the thread-supply cone.

or any other stitch employing a back thread or to any stitch in which loops are exposed on the front and/or hack of the fabric to an extent as to permit the loopengaging pins to restrain the thread from being drawn to a taut position against the faces of the fabric.

Referring to the drawing, 1 indicates the head of a known type of sewing machine, the same being provided with the vertically-reciprocating needle bar 2, provided at its lower end with the head 3 in which one or more needles are fitted, two of the same being shown at 4 and 5. It will be understood that the needle bar is vertically reciprocated in the known manner by conventional sewwhich is removably attached a presser foot shown at 8. The presser foot 8 is provided at one end with a pair of upstanding lugs 9 each of which is formed with a hole It) through which a screw or pin 11 is extended to thereby attach the presser foot 8 to the head 7 and locate it in the required operative position below the needles, as clearly seen in FIG. 1. I

Extending vertically through the presser foot and between the lugs 9 thereon and the upwardly-directed forward end 12a of the presser foot, is a pair of slots indicated respectively at 12 and 13. These slots are located below the respective needles 4 and so that the needles, upon descending, will pass through the slots and reach and penetrate the fabric then located under the presser foot.

Inserted transversely through the presser foot are rods or pins indicated respectively at 14 and 15. These rods or pins are disposed horizontally and are at right angles to the direction of reciprocating movement of the needles. The rod or pin 14 enters into the presser foot through an opening 16 provided therein and is held in the required position in the presser foot by means of a set screw 17 (FIGS. 1 and 6). The end of the rod or pin 14 is located in the slot 13, and it projects approximately one-half of the distance across the slot or slightly more than half way, and it clears the needle 4 entering through said slot. The rod or pin similarly enters into the presser foot through the opening 18 and is held in the proper position theerin by means of a screw 19. The end of the rod or pin 15 should project approximately half way or slightly more than half way across the slot 12 as shown in FIG. 6 and should be located to clear the needle 5.

This arrangement, consisting of the provision of a rod or pin in the presser foot for each of the needles, is such that as the needles descend to pass through the cloth, the thread is brought over the pins 14-, 15. After the stitch is formed and as the needles ascend out of the fabric and tension is put on the thread, the thread slides off the pins. Since the pins are disposed between the fabric and the thread while each stitch is being formed, more thread than normally required is used in making the stitch and the desired slackness in each upper loop of the seam will result.

Means is required for the provision of the additional thread for the production of the looseness or slag above described and for this purpose the mechanism disclosed in the upper portion of FIGS. 1 and 2 and in PEG. 5 is provided. Carried by the needle bar 2 is a cam 25, the same being clamped on the needle bar by means of a screw 26. Said cam is operative against a roller 27 rotative on an axle 23 mounted in a clevis 29. At its end remote from the roller 27, the clevis is formed with a stud portion 30 secured in the recessed end of a bar 32 by means of a cross-pin 31.

The bar 32 is longitudinally slidable through the central opening 34 of a cap 33 fitted on and secured to the headed end 35 of a cup 36 by means of the fastening screws 37. The cup 36 is fixedly mounted in the head 1 of the machine by means of a pin or screw shown at in FIG. 1.

At one end the bar or arm 32 has an integral collar 38 which is slidable piston-like within the cup 36 and a coil spring 39 has one end engaging against the collar 38 and its other end seated against the cap 33. At its free end, the bar 32 is provided with the thread guides 40 and 41. The spring 3 is effective to urge the movable part of the above mechanism, consisting of the bar 32 and attached clevis 29 and roller 27 toward the cam so that as the cam 26 is carried upwardly by the needle bar 2, on the raising movement of the latter, the cam will contact roller 27 which causes the bar or arm 32 to be moved outwardly or toward the right as viewed in FIG. 1, so that the required additional thread will, at the proper time, be drawn from the supply cone. Also, at the proper time, the arm or bar 32 will be released so that there is no tension on the thread then going into the stitch, thus allowing the stitch to be formed with a minimum of tension on the thread.

In addition to the rods or pins 14 and 15 which produce slack or looseness in the upper loops of a seam, means is also provided for the production of slack in the lower loops. The mechanism for this purpose is shown in the lower portion of FIGS. 1 and 2. There is therein shown a rotative shaft 56, which may be the bobbin-carrying shaft of the sewing machine, and which shaft carries a cam 51, the operative face of which is engaged by a roller 5'23, rotative on a pin 53 in an angular arm 54.

Secured to the top of the arm 54 is a plate 55, from one end of which projects a pair of rods or pins 56 and 57. The plate is suitably guided in a slot in the bed plate 58 of the machine, possibly somewhat similar to the arrangement shown in the co-pending application Serial No. 172,494, and under the impulse of the camv 51 it causes the pins or rods 56 and 57 to enter behind the needles and between the thread and needles so that as stitches are formed, the pins are in such position, resulting in additional thread being used to form the stitches and creating the desired slack or loosenessin the lower loops thereof.

When each stitch is thus formed and just before the needle rises out of the cloth, the pins 56 and 57 retract under pressure of the spring 59, resulting in a completely formed stitch using more thread than usual. The spring 59 has one end bearing against a fixed element 60 on the machine and its other end engaging against the end of a pin 61 attached to the plate 55 by means of a stud 62.

By mean of the arrangement described, slack or'looseness can be so provided in the loops of the thread forming a seam, thereby compensating for thread shrinkage and avoiding undesirable puckering in the fabric of a garment adjacent to the seam therein.

Having thus described a single embodiment of the invention, it is obvious that the same is not to be restricted thereto, but is broad enough to cover all structures coming within the scope of the annexed claims.

What we claim is:

l. A sewing machine having a presser foot provided with an opening extending through it, a needle bar, a needle carried by said needle bar and movable through said opening during the stitching operation, at least one pin inserted in the presser foot and disposed substantially at right angles to the direction of movement of the needle, said pin having an end portion extending into the opening and projecting partly across the same whereby upper loops formed in the thread insertable by the needle will be extended over said end portion of the pin, at least one movable pin operable below the material being sewed for engagement with the lower thread loops, both of the abovedescribed pins being effective to provide for slight upper and lower loop slackness in both threads of the stitching, and means for intermittently relieving tension in the thread supplied to the needle during the forming of the loops, said means comprising a cam mounted on the needle bar, a follower havini a first part and second part, a member supporting the follower, a resilient means engaging the follower and the support member for biasing the first part of the follower into engagement with the cam, thread guides positioned on the second part of the follower opposed from the first part for guiding the thread outwardly when the follower is caused to move in the same direction to thereby place the thread under tension and to relax the tension when the follower is caused to move inwardly.

2. The sewing machine as defined in claim 1 wherein the follower first part includes a roller engaging said cam.

3. The sewing machine as defined in claim 1 wherein the supporting member for the follower includes a housing at least partially encasing the follower.

4. In a sewing machine as provided for in claim 1, wherein means is provided for withdrawing some of the pins from the loops formed over them and the other pins being so disposed that the loops which were formed over them will slip off said pins upon needle withdrawal from the material in which the stitching is inserted.

References ited by the Examiner UNITED STATES PATENTS CJI 6 Gatcheil 112-245 Hanson 112-255 X Grossman 112-235 De Simone 112-226 Donaldson 112-262 X Parry 112-154 Weschler 112-235 Sachs 112-262 X 10 JORDAN FRANKLIN, Primary Examiner. DAVID J. WILLIAMOWSKY, Examiner. 

1. A SEWING MACHINE HAVING A PRESSER FOOT PROVIDED WITH AN OPENING EXTENDING THROUGH IT, A NEEDLE BAR, A NEEDLE CARRIED BY SAID NEEDLE BAR AND MOVABLE THROUGH SAID OPENING DURING THE STITCHING OPERATION, AT LEAST ONE PIN INSERTED IN THE PRESSER FOOT AND DISPOSED SUBSTANTIALLY AT RIGHT ANGLES TO THE DIRECTION OF MOVEMENT OF THE NEEDLE, SAID PIN HAVING AN END PORTION EXTENDING INTO THE OPENING AND PROJECTING PARTLY ACROSS THE SAME WHEREBY UPPER LOOPS FORMED IN THE THREAD INSERTABLE BY THE NEEDLE WILL BE EXTENDED OVER SAID END PORTION OF THE PIN, AT LEAST ONE MOVABLE PIN OPERABLE BELOW THE MATERIAL BEING SEWED FOR ENGAGEMENT WITH THE LOWER THREAD LOOPS, BOTH OF THE ABOVEDESCRIBED PINS BEING EFFECTIVE TO PROVIDE FOR SLIGHT UPPER AND LOWER LOOP SLACKNESS IN BOTH THREADS OF THE STITCHING, AND MEANS FOR INTERMITTENTLY RELIEVING TENSION IN THE THREAD SUPPLIED TO THE NEEDLE DURING THE FORMING OF THE LOOPS, SAID MEANS COMPRISING A CAM MOUNTED ON THE NEEDLE BAR, A FOLLOWER HAVING A FIRST PART AND SECOND PART, A MEMBER SUPPORTING THE FOLLOWER, A RESILIENT MEANS ENGAGING THE FOLLOWER AND THE SUPPORT MEMBER FOR BIASING THE FIRST PART OF THE FOLLOWER INTO ENGAGEMENT WITH THE CAM, THREAD GUIDES POSITIONED ON THE SECOND PART OF THE FOLLOWER OPPOSED FROM THE FIRST PART FOR GUIDING THE THREAD OUTWARDLY WHEN THE FOLLOWER IS CAUSED TO MOVE IN THE SAME DIRECTION TO THEREBY PLACE THE THREAD UNDER TENSION AND TO RELAX THE TENSION WHEN THE FOLLOWER IS CAUSED TO MOVE INWARDLY. 